The present invention relates to a system for displaying concept networks, and more particularly to a network display system which efficiently displays knowledge stored with a network structure in an electronic file, using a computer with a multi-window display capability.
Recently, small-sized, large-capacity storage devices, such as optical disc storages have become available for use as document filing devices in offices. The operations of such devices, such as management and retrieval of a data base, which conventionally allows specialists to store and/or retrieve a large amount of data, are now performed directly by end users. Systems in which knowledge bases are applied to such filing systems are described, for example, in U.S. application Ser. No. 844,123, filed Mar. 26, 1986, now U.S. Pat. No. 4,868,733.
The expression of knowledge in the knowledge base used in the system disclosed in application Ser. No. 844,123 will now be described with reference to FIG. 3 which shows the scheme of a concept. In FIG. 3, an ellipse and an arrow represent a concept and a relation, respectively. In the knowledge base, all concepts are combined in a subsumption relation where the concept "UNIVERSAL" is the anchor concept. The subsumption relation represents the relationship "A concept X is one of concepts Y". A concept ranking high compared with a reference concept is referred to as a superconcept while a concept ranking low compared with the reference concept is referred to as a subconcept. For example, in FIG. 3, the superconcepts for a "COMPUTER" 311 are "UNIVERSAL" 301, "MATTER" 305, and "HARDWARE" 310. Concepts put general concepts in a generic relation. When the relationship between two concepts is expressed in general terms, two different names are obtained depending on which of the two concepts is handled as a main one. For example, concept "ORGANIZATION" 306 and "HARDWARE" 310 may be considered together by the generic relation "DEVELOPMENT" 324. The name of that relation has two definitions, "HARDWARE" which the "ORGANIZATION" "HAS DEVELOPED", and "ORGANIZATION" which "HAS DEVELOPED" the "HARDWARE". An instance relation puts pieces of instance knowledge in a relationship. In order to establish such relationship, superconcepts must be combined by a generic relation with the same relation name. For example, concept "HITACHI, LTD." 309 and concept "2050" 314 are combined by the instance relation "DEVELOPMENT" 328. The user can browse through concepts stored in a knowledge base, and the concept which the user notes in his browse is hereinafter referred to as a current concept.
There are several knowledge base display systems, as disclosed, for example, in U.S. application Ser. No. 06/844,123, now U.S. Pat. No. 4,868,733. The proposed system is of the type which uses commands which are executed for all current concepts. A command tree is prepared for display of a concept tree in a subsumption relation. If a command tree for display of a concept tree, the depth m of the displayed concept tree, and a branching factor of n, are input as [tr m n], the tree of the current concept and other concepts of the same ranking level and subconcepts for the current concept will be displayed with a depth m and a branching factor n. A command wh is prepared for display of a superconcept for the current concept. If [wh] is input, the superconcept for the current concept is displayed. A command fr is prepared for display of a concept frame which displays an instance relation attached to the current concept. If [fr] is input when the current concept is "2050", a frame of "2050" is displayed. For example, "HITACHI, LTD. DEVELOPED" is displayed in a first line of the frame, "WHICH RUNS UNDER HI-UX" is displayed in a second line, and "WHOSE SUBJECT IS ARTICLE #02" is displayed in a third line. By giving a command "fr 2", a frame for the concept "HI-UX" in the second line of the displayed frame is further displayed.
Since the history of concepts in which the user moved the current concept is not stored in memory, the concepts must be searched again in order that the concept searched before is again the current concept. Generally, there is a "back-trace function" as a means for tracing the history. If the "back-trace function" is used as a means for tracing the history of the current concept, and the current concepts move in the order of "2050", "HITACHI, LTD.", "2050", and "HI-UX", the history will be traced in the order of "HI-UX", "2050", "HITACHI, LTD." and "2050" by inputting a command "bt" for tracing purposes.
The above prior art has the following problems, so that it cannot provide a flexible display and therefore it is difficult to browse.
Since each operation is performed on a command basis, respective commands for display of a concept tree, a concept frame and a superconcept must be entered in order to obtain data on the concept.
In a concept tree display, a branching factor and a depth are designated for display of concepts ranking low compared with the current concept. Since a concept tree is displayed necessarily using the current concept as the anchor concept, however, a world which includes the current concept including the anchor concept, and concepts of the same ranking level cannot be displayed using a concept tree. Therefore, when it is desired to know concepts of the same ranking level as, or of a higher ranking level than, the current concept, the current concept must first be moved to the position of a superconcept and the concept tree must again be displayed. In addition, since the concept tree cannot be displayed by solely defining the concept tree with a branching factor and a depth, the user cannot collect and display portions of the concept tree which the user is interested in. Therefore, when it is desired to display in detail part of a displayed concept tree, the branching factor and depth must be changed to rewrite the concept tree or the current concept must be moved to a superconcept for a portion of the tree which the user desires to know in detail, and commands for display of the concept tree must be entered to rewrite the display of the concept tree. If the values of the branching factor and depth are increased, however, the number of concepts to be displayed is increased, so that they cannot be viewed on a single display screen. Conversely, if the values are decreased, desired information cannot be viewed and hence operability is low.
Even if the command "bt" is used as means for tracing the history, the concepts can only be arranged in the order of movement of the current concept. For example, even when the current concepts moved in the order of "2050", "HITACHI, LTD.", "2050", and "HITACHI, LTD.", display is effected in this order. Therefore, when the same concept becomes the current concept many times, it is displayed each of those times to thereby render it impossible to trace the history.
As just described above, according to the operation of the above-referenced system, it is very difficult to appropriately display data which the user needs.